Cyclic AMP-Phosphodiesterase Activity and Histamine Release in Cord Blood Leukocyte Preparations

Abstract

Atopic dermatitis, allergic rhinitis and asthma are a common group of diseases with a familial predisposition. At present there is no suitable predictive or diagnostic marker. Adults with atopic dermatitis or allergic respiratory disease have elevated mononuclear leukocyte cAMP-phosphodiesterase activity. This activity correlates closely with histamine release from basophils. We investigated newborn leukocyte phosphodiesterase activity and histamine release in umbilical cord blood. Phosphodiesterase activity was significantly elevated in cord blood leukocytes of 81 children with a positive history of atopy in first degree relatives, compared to 33 children with a negative history (p less than 0.025). In contrast to adults there was no correlation between phosphodiesterase activity and histamine release. Our studies suggest that elevated phosphodiesterase activity is a primary, genetically linked defect. Fetal basophils would appear to possess cytophilic IgE since they are capable of immunologically stimulated histamine release even without passive, in vitro IgE sensitization. In addition, there are functional differences between adult and cord blood basophils. Longitudinal studies may determine if elevated phosphodiesterase is predictive of atopic states.